Prestressed furniture spring



Dec. 5, 1967 BQND PREsTREssEn FURNITURE SPRING 2 Sheets-Sheet 1 Original Filed Sept. 28. 1964 R mm me Id .N d

Dec. 5, 1967 J. J. BOND 3,356,359

FRESTRESSED FURNITURE SPRING Original Filed Sept. 28, 1964 2 Sheets-Sheet 2 INVENTOR. y Jo/A/ J BOA/o A o ars United States Patent O 3,356,359 PRES'ERESSED FURNITURE SPRING .lohn i. .ET-ond, Wiclrcnberg, Ariz., assiguor, by mesne assignments, to Lear Siegler, Enc., Santa Monica, Calif., a corporation of Deiaware Continuation of application Ser. No. 399,700, Sept. 28, 1964. This application May 23, 1967, Ser. No. 640,627

Claims. (Cl. 267-102) ABSTRACT 0F THE DISCLGSURE A spring assembly including a sinuous spring extending across a furniture frame ,and including an angularly olfset portion defining an integral prestress lever. And an auxiliary spring to .be disposed in engagement with any sinuous spring but providing particular advantages when attached to the integral prestress lever portion for reinforcing same.

Thisapplication is a continuation of copending appli-A cation Ser. No. 399,700, tiled Sept.w28, 1964, and assigned to the assignee of the instant invention.

This invention relates generally to :an improved prestressed spring arrangement for furniture and more particularly to an integral sinuous spring structure that is shaped to produce the prestress forces when it is assembled `to the furniturefname Without the aid of separate appliances.

Patent No. 2,958,375 issued on Nov. l, 1960, describes the advantages of prestressing sinuous springs in furniture applications from an arcuate configuration when the spring is relaxed, to a substantially rectilinear shape when the prestress forces are applied. The patent discloses a prestress lever that is arranged to be mounted in the furniture spring assembly to apply a force that serves to prestress the pring from its relaxed arcuate position to a prestressed flattened or rectilinear position.

lt is a general object of the present invention to provide an improved sinuous furniture spring that may be prestressed in the spring assembly without the use of extrane-y ous levers for producing the prestress forces.

Another object is to provide a sinuous furnitu-re spring with a prestress lever incorporated as an integral part of the spring.

Another object of the present invention is to provide a reinforcing structure for attachment to the spring at the point wherethe prestress forces are applied to prevent these forces from straining the spring beyond its elastic limits. f

Another object is to provide auxiliary springs to supplement the sinuous springs of a furniture spring assembly with an auxiliary spring being mounted on each sinuous spring in a manner to reinforce the sinuous spring for preventing the prestress forces from straining the spring beyond its elastic limits.

A further object is to provide a sinuous furniture spring assembly of simple and vinexpensive construction that is sturdy and eiiicient in operation. v

According to this invention the improved sinuous spring construction provides for shaping either both or one end of each length of sinuous spring so that the end departs from the normal path of the spring when the latter is in the relaxed condition. Such distorted end constitutes an integral prestress lever that serves to apply Ia prestress force to the spring when the latter is assembled to the furniture fname to cause the spring to be flattened from its relaxed arcuate position into a prestressed rectilinear position that possesses the ideal characteristics forv a furniture spring. However, the prestress forces applied to the spring produce anexcessive strain at the end of the spring where the integral prestress lever is formed and 3,356,359 Patented Dec. 5, 1967 such strain would tend to distort the conventional spring beyond its elastic limits which would result in a permanent set of the spring.

In order to alleviate this prestress strain on theA sinuous springs, the auxiliary springs that normally supplement the sinuous springs are clipped onto the sinuous springs in such a manner as to reinforce the sinuous springs at the point where the excessive strains will occur. Such reinforcement enables the sinuous springs to withstand the prestress forces and renders it possible to incorporate the prestress lever integrally with the sinuous springs.

The foregoing and other objects of the invention, which will ibecome more fully apparent from the following detailed description, may be kachieved by means of the apparatus described in connection with the accompanying drawings in which:

FIGURE l is a plan view of a sinuous spring assembly for a chair which is mounted on a fra-me and incorporates the present invention;

FIGURE 2 is a view in vertical section taken along the plane represented Iby the line 2 2 in FIGURE 1;

FIGURE 3 is a perspective detail View of the auxiliary spring that is especially adapted to complement the sinuous spring which incorporates the integral prestress lever construction of the present invention;

FIGURE 4 is a side elevational View of a sinuous spring incorporating the integral prestress lever of the present invention. with the spring being depicted in the relaxed condition;

FIGURE 5 is an enlarged fragmentary perspective view showing the end of a sinuous spring attached to the furniture fname;

FIGURE 6 is an enlarged fragmentary View pa-rtly in vertical section and partly in side elevation illustrating the auxiliary spring that is shown assembled to the sinuous spring in FIGURE 3;

FIGURE 7 is a diagrammatic view illustrating several possible positions of the sinuous spring when mounted in a furniture spring'assembly; and

VFlGURE 8 is a diagrammatic view of a portion of a sinuous spring compressed together by a load.

Reference is now made more particularly to the drawings :and specifically to FIGURE 1 thereof which illustrates a sinuous spring assembly forthe seat of a chair. The assembly includes four sinuous springs 10 mounted on av chairl iframe generally identified by the reference numeral 11. The'chair frame comprises a front member 12 and a lback member 13 that are secured between two side mem-bers 14 and 15 to form the rectangular frame 11 upon which the sinuous springs 10 are mounted to constitute the frame and spring assembly for the seat of a chair.

The sinuous Vsprings 10 are formed from a length of spring wire 'formed'to follow .a sinuous path ias best shown in FIGURE l. As a result, each of the springs comprises a plurality of parallel reaches 2G that are joined to each other by semi-circular portions 21. Thus, each of the reaches Ztl is joined to the preceding parallel reach 20 by a semi-circular portion 21 on one side of the spring 1G and to the succeeding reach 20 by another semi-circular portion 21 on the opposite side of the spring 10.

When the springs 10 are relaxed they assume an arcuate configuration, preferably of substantially circular form as illustrating in FIGURE 4. When applied to the furniture frame, they are stressed out of their relaxed condition into a position to stretch across the frame 11 with one end of each ofthe springs being attached to the back frame member i3 and the opposite end being coupled to the front frame member 12 as depicted in FIGURES l and 2. To this end, a plurality of clips Z2 are fixed to the top edge of the frame member 13 with one clip 22 lbeing provided for each of the springs 10. The specific spring assembly illustrated in the drawings provides four springs so that four clips 22 are fixed to the frame member 13. Each of the clips 22 is provided with a tubular portion 23 for receiving the end of its associated sinuous spring 1t). The extremity of the spring extends beyond the tubular portion 23 and is bent slightly to secure the spring to the clip 22 as clearly illustrated in FIGURE 1.

As best shown in FIGURES 2 and 5, the opposite end of each of the springs 10 is coupled to the frame member 12 by a wire clip 25 that is pivotally supported by a bracket 26 which is fixed to the Iframe member 12. The pivotal mounting of the clip 25 permits a slight yielding movement which is desirable at the forward end of the springs 10. If a stiffer mounting is desired the clip 25 may be omitted and the end of the spring 10 attached directly to the bracket 26 or otherwise fastened to the frame member 12 in well known manner. p

In the past it was the accepted practice to mount both ends of the spring 10 to the frame members in the same manner as the rear ends of the springs 10 are shown mounted to the back member 13 of the frame 11 in FIG- URES 1 and 2. This resulted in the springs 10 following a pronounced arcuate path as represented by the solid line 27 in FIGURE 7. When a load is placed upon a spring that is supported in this arcuate position, the arc of the spring is flattened and when it reaches the substantially horizontal position represented by the dotted line 28 in FIGURE 7, the reaches not only respond to torque by rotation about the longitudinal axis of each reach, but also, since the arc is being flattened and the length of the band is shortened, the respective reaches will no longer be parallel with one another, but rather, will diverge toward each other to the position depicted in FIGURE 8. As this occurs, a maximum amount of compressive stress is placed upon the semi-circular portions 21 of the spring, and as the latter moves on down into the position represented 'by the broken lines 29 in FIGURE 7, the spring action of the semi-circular portions 11 is relieved to permit the spring to eiongate to accommodate the position represented by the broken line 29 in FIGURE 7. As a result, the flexing of the spring 10 from the position represented by the broken line 29 involves a continual increase in the torsional stresses upon each of the reaches 20, but the torsional strength of the reaches 20 is not only overcome by the load applied to the spring but also by the opposing spring action and the relieving of stresses in the semicircular portions 21 of the spring. Accordingly, after the load on the seat has forced the spring 10 past the horizontal arc represented by the dotted line 23 in FIGURE 7, the forces developed by the spring itself act to move the spring beyond the horizontal position so that the spring reacts to the load to a much greater extent after the spring has passed the horizontal position. Because of this charac-A teristic the capacity of the spring is reduced substantially.

This undesirable characteristic of sinuous furniture springs was first overcome by a prestress lever disclosed in said Patent No. 2,958,375 issued on Nov. 1, 1960. The prestress lever described in that patent prestresses the sinuous spring to the rectilinear horizontal position represented by the dotted line 28 in FIGURE 7 with the reaches parallel to each other to thereby avoid the compression of the reaches 20 to the position shown in FIG- URE 8. Instead, when a load is applied to a sinuous spring that is prestressed to the horizontal'fposition, the parallel reaches 10 diverge relative to each other and therefore full advantage is taken of the torsional strength of the reaches 20 throughout the limits of the spring movement. As a result, a substantially uniform displacement of the sinuous spring 10 occurs per unit of load applied which is a desirable characteristic in a furniture spring. The only disadvantage of such prestressed spring arrangement lies in the fact that a separate prestress lever was required for each sinuous spring in the assembly, and if a fully rectilinear position was desired a prestress lever was required for each end of the spring. The present invention overcomes this disadvantage by incorporating the prestress lever as an integral part of the spring 10 to obtain the same characteristics that were previously produced through the use of the prestress levers disclosed in said patent.

The integral prestress lever is produced in the sinuous spring 10 by the simple expedient of forming the spring so that when it is in the relaxed position shown in FIG- URE 4 either one or both ends of the spring are displaced from the relaxed path of the other portion of the spring so that the displaced portion constitutes the prestress lever. Although other proportions and angles may be provided to accommodate the particular spring structure and its specific characteristics, the illustrated embodiment shows a prestress lever 30 formed at only one end of the spring 10 and it is formed by bending a portion of the spring 10 to displace the last two semicircular portions 21 and their associated reaches 20. This end portion of the spring 10 is displaced so that it extends inwardly from the circular path of the spring 10 to a position approximately 15 from the radius of the circle when the spring 10 -is in its relaxed position. The mounting of the spring 10 on the frame 11 causes the prestress lever 30 to apply a stress to the spring which forces it from the arcuate position represented by the solid line 27 in FIGURE 7 to the horizontal position as depicted in FIGURE 2 and represented Iby the horizontal line 28 in FIGURE 7. Since the prestress lever 30 is applied to only the forward portions of the springs 10 in the illustrated embodiment, approximately the forward two-thirds of the springs assume the horizontal position. The absence of the prestress lever 30 at the rear portion of the springs permits the rear one third of the springs to follow the more arcuate path depicted in FIGURE 2. It should be understood that the prestress lever 30 may be applied to both ends of the spring 10 to cause the entire length of the spring 10 to follow a rectilinear path and the arcuate configuration of the back one third of the springs as illustrated in FIG- URE 2 will be eliminated. However, in most chair construction the arcuate configuration of the rear portion of the spring is not particularly detrimental and it is depicted in the illustrated embodiment for the purpose of more clearly illustrating the affect that the integral prestress lever 30 has on the spring. Thus, the illustrations show the effect of the prestress lever 30 at the front end of the spring and the rear portion of the spring represents its portion when the prestress lever 30 is omitted.

As best shown in FIGURE 2, the integral prestress lever 30 extends upwardly from the front member 12 at an angle of approximately 45 toward the rear member 13 of the frame 11. From the top of the prestress lever 30 the sinuous spring 10 extends substantially horizontally until it begins to arc downwardly through approximately the last one third of its length into engagement with the back member 13. This arrangement of the prestress lever 30 leaves a gap from the forward surface of the front member 12 to the top of the prestress lever 30. In order to extend the horizontal surface of the spring assembly to the forward surface of the front member 12 and overlie the gap at the forward portion of the frame 11 to provide a proper support for upholstery, a wire frame 35 is attached to one of the reaches 20 of the sinuous springs 10 Iby clips 36 in Well known manner. The wire frame 35 extends from its point of attachment with the sinuous springs 10 forwardly to extend approximately to the plane of the forward surface of the front member 12 as depicted in FIGURE 2. The forwardly extending wire member of the frame 35 is supported `by four auxiliary springs generally identied -by the reference numeral 44, one of which is provided for each of the sinuous springs 10. In addition, a rod 37 extends across the spring assembly and is fastened to each of the springs 10 by a clip 38. The rod 37 serves to tie the several springs together so that they function cooperatively and are not displaced excessively relative to each other.

As best shown in FIGURE 3, the auxiliary spring 44 comprises a at sheet metal body 40 that has one end split by a kerf 45 to form a pair of leaves 41 that are bent `backwardly to overlap the body 40. The overlapping leaves 41 constitute clips formed integrally with the auxiliary spring 44 for attaching the forward end of the latter to the front wire of the frame 35. The overlapping leaves 41 are shown in their open position in FIGURE 3 spaced from the |body portion 40 to furnish an access for the passage of the wire of the frame 35 into a crook 46 formed by the bending of the leaves 41 rearwardly over the body 40. The wire of the frame 35 is depicted by broken lines in FIGURE 3 disposed within the crook 46. The wire is secured in this position by the simple expedient of bending the leaves 41 downwardly about the Wire and into engagement with the surface of the body 40 in the manner illustrated in FIGURE 6 where the auxiliary spring 44 is shown secured to the frame 35 by its integral clip formed by the overlapping leaves 41.

The opposite end of the auxiliary spring 41 is attached to the sinuous spring at the integral prestress lever 30 in the manner illustrated in FIGURES 3 and 6. It is attached to the prestress lever 30 by a hook 42 and a catch 43 that are integrally formed with the body 40 by bending the end of the body opposite the end on which the leaves 41 are formed. Thus, the rearward end of the body 40 is bent downwardly and toward the underside of the body to provide an underlying portion 50 which forms the hook 42. The end of the underlying portion 50' is bent approximately 100 outwardly in a direction away from the body 40 to form the catch 43.

As shown in FIGURE 6, the hook 42 is engaged Yabout one of the reaches of the sinuous spring 10 and the reach that is engaged by the hook 42 is identified in FIGURES 3 and 6 by the reference numeral 20A. The catch 43 is latched in the opposite direction about a reach B to rmly secure the auxiliary spring 44 to the sinuous spring 10. The mounting of the auxiliary spring 44 may be easily accomplished by passing the latch 43 between the two reaches 20A and 20B until the hook 42 engages the reach 20A. The auxiliary spring 44 is then pivoted in a clockwise direction, as viewed in FIGURE 6, about the reach 20A to engage the latch 43 about the reach 20B. The frame 35 is then positioned to place its forward wire in the crook 46 and the leaves 41 are bent about the frame 35 and into engagement with the body 4d to secure the auxiliary spring 44 in position.

The auxiliary spring 44 is a well known expedient for overlying the gaps formed at the extremities of the sinuous spring construction and it supports the frame 35 in an upward position over the front member 12 to provide the proper base for upholstery that is applied about the frame 11 and over the springs 10. However, in the present invention, the auxiliary spring 44 serves a further purpose of reinforcing the sinuous spring 10 for resisting the high forces that are developed by the integral prestress lever 30. It will be noted from the view in FIGURE 6 that, as previously mentioned, the spring 10 is bent to displace the first two semi-circular portions 21 and their associated reaches 20 from the normal path followed by the conguration of the sinuous spring 10 when it is in the relaxed condition. The displaced portion forms the prestress lever 30. When the spring 10 with its cooperating prestress lever is applied to a furniture frame as shown in FIG- URE 2, the force required to prestress the spring 10 into its rectilinear position is substantial and with the repeated exing of the spring 10 when in use places a great strain on the semi-circular portion 21 that unites the two reaches 20A and 20B illustrated in FIGURE 6. This force has a tendency to distort the semicircular portion 21 beyond its elastic limits to cause the reaches 20A and 20B to diverge which would damage the spring and disturb its desirable characteristics. The hook 42 and the latch 43 of the auxiliary spring 44 are designed specifically for the purpose ofnot only attaching Vthe auxiliary spring 44 to the sinuous spring 10, but also to reinforce the spring by engaging the reaches 20A and 20B and retaining them in their parallel positions. Since the hook 4Z and latch 43 retain the reaches 20A and 20B in their parallel positions they prevent the associated semicircular portion 21 from being distorted so that the proper sinuous coniiguration of the spring 10 is maintained throughout its length despite the large forces that are developed in the portion containing the integral prestress lever 30.

Thus, a sinuous spring 10 formed of conventional gauge wire may be shaped to create a prestress lever 30 formed integrally with the spring to prestress the length of sinuous spring so that it occupies a rectilinear path when mounted to a furniture frame. Although the prestress forces plus the usual forces that occur during normal use may be beyond the capacity of the spring to withstand, the hook 42 and latch 43 of the auxiliary spring 44 cooperate with the spring to reinforce it at the point where the excessive forces are applied to assist the spring in withstanding them. As a result, the spring is at no time strained beyond its elastic limit.

From the foregoing detailed description of the construction and operation of the illustrative embodiment of the present invention it Will become apparent that a new and improved sinuous spring construction has been provided in which a prestress lever is incorporated integrally with a sinuous furniture spring for improving the characteristics of the spring when the latter is mounted on a furniture frame by providing the proper prestress forces through the medium of the integral prestress lever. Moreover, the auxiliary spring which conventionally supplements the sinuous spring is constructed in a unique manner to reinforce the sinuous spring at the point where the excess prestress forces are developed to prevent damage to the spring.

Although the illustrative embodiment of the present invention has been described in considerable detail for the purpose of making a full disclosure of a practical operative arrangement by means of which the invention may be practiced, it is to be understood that Various novel features of the invention may be incorporated in other arrangements without departing from the spirit and scope of the invention as defined in the subjoined claims.

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. In a spring assembly for mounting ona furniture frame; a sinuous spring shaped to have its length Ifollow an arcuate path when said spring is in its relaxed condition, a prestress lever formed by a portion displaced from the relaxed path of the remainder of the spring, said prestress lever supported by the furniture frame and coupled to said sinuous spring, said prestress lever exerting a prestress force on said sinuous spring to flatten its arcuate coniiguration when said spring is mounted on the furniture frame to improve the characteristics of said spring for furniture applications; an auxiliary spring extending from said sinuous spring to provide a spring support at an extremity of the furniture frame; mounting means for mounting said auxiliary spring to said sinuous spring; and reinforcing means on said auxiliary spring in engagement with said prestress lever to reinforce said prestress lever to avoid damage to the spring by the prestress forces.

2. In a spring assembly for mounting on a furniture frame; a sinuous spring shaped to have its length follow an arcuate path when said spring is in its relaxed condition; a prestress lever formed by a portion displaced from the relaxed path of the remainder of the spring, said prestress lever formed integrally with said sinuous spring to prestress said spring and thereby flatten its arcuate configuration when said spring is mounted on the furniture frame to improve the characteristics of said spring; an auxiliary spring extending from said sinuous spring to provide a spring support at an extremity of the furniture frame; mounting means for mounting said auxiliary spring to said sinuous spring; and reinforcing means on said auxiliary spring in engagement with said prestress lever to reinforce the portion of said sinuous spring that is subjected to the maximum strain due to the forces developed by the action of said prestress lever.

3. In a spring assembly for mounting on a furniture frame; a sinuous spring comprising a plurality of parallel reaches disposed transverse to the length of said spring and connected to each other successively by semi-circular portions, said sinuous spring being shaped to have its length follow an arcuate path when said spring is in the relaxed condition; a prestress lever formed integrally with said sinuous spring and comprising the last several reaches at the end of the spring and their cooperating semicircular portions followingr a path that departs from the arcuate path of the relaxed spring; means for mounting said prestress lever to the furniture frame so that said prestress lever stresses the spring in a manner to cause the spring to flatten out from its arcuate path to improve its characteristics; a wire frame overlying said sinuous spring and extending outwardly therefrom to the extremity of the furniture frame; an auxiliary spring extending from said sinuous spring over said prestress lever to provide a spring support at the extremity of the furniture frame; means for securing said auxiliary spring to a plurality of said reaches of the spring; and a clip at the end of said auxiliary spring and formed integrally therewith for attaching said auxiliary spring to the extending portion of said wire frame.

4. In a spring assembly for mounting on a furniture frame; a sinuous spring comprising a plurality of parallel reaches disposed transverse to the' length of said spring and connected to each other successively by semicircular portions; coupling means for coupling the ends of said sinuous spring to the furniture frame; a wire frame overlying said sinuous spring and extending outwardly therefrom to the extremity of the furniture frame; an auxiliary spring extending from said sinuous spring over said Coupling means to provide a spring support at the extremity of the furniture frame; a hook on said auxiliary spring hooked over a first reach of said sinuous spring; a catch on one end of said auxiliary spring in engagement with a second reach of said sinuous spring to prevent said hook from being inadvertently displaced relative to said first reach and to thereby firmly secure said auxiliary spring to said sinuous spring; and a clip formed integrally on the opposite end of said auxiliary spring for clipping said auxiliary spring to said frame.

5. In a spring assembly for mounting on a furniture frame; a sinuous spring comprising a plurality of parallel reaches disposed transverse to the length of said spring and connected to each other successively by semicircular portions, said sprin g being shaped to have its length follow an arcuate path when said spring is in the relaxed condition; a prestress lever formed integrally with said sinuous spring and comprising the last several reaches at the end of the spring and their cooperating semicircular portions following a path that departs from the arcuate path of the relaxed spring; means for attaching said prestress lever to the furniture frame so that said prestress lever stresses the spring in a manner to cause the spring to flatten out from its arcuate path to improve its characteristics; an auxiliary spring extending from said sinuous spring over said prestress lever to provide a spring support at the extremity of the furniture frame and comprising an auxiliary spring body formed of pliable sheet material; a hook formed integrally with Said body by bending a portion of the sheet material backwardly to overlap said body, said hook being adapted to hook about a first reach of said sinuous spring; a catch formed integrally with said body by bending an extremity of the sheet material adjacent to said hook outwardly of said hook and said body; and a clip formed integrally with said body at the end opposite said catch by bending the sheet material backwardly into overlying relationship with said body, said clip serving to attach said auxiliary spring to members of the spring assembly.

6. In a spring for mounting on a furniture frame; a sinuous spring shaped to have its length follow an arcuate path when said spring is in its relaxed condition; a prestress lever formed integrally with said sinuous spring to prestress said spring and thereby flatten its arcuate configuration when said spring is mounted on the furniture frame to improve the spring action of said spring for furniture applications; and means coacting with said prestress lever for reinforcing said spring to assist it in withstanding the forces developed by said prestress lever.

7. In a spring assembly for mounting on a furniture frame; a sinuous spring extending across the furniture frame and including a prestress lever to prestress said spring; an auxiliary spring extending from said sinuous spring to provide a spring support at an extremity of the furniture frame; mounting means for mounting said auxiliary spring to said sinuous spring; and reinforcing means on said auxiliary spring in engagement with said prestress lever to reinforce a portion of said sinuous spring.

8, In an auxiliary spring adapted to be mounted on a sinuous spring which comprises a plurality of parallel reaches disposed transverse to the length of the spring and connected to each other successively by semicircular portions; an auxiliary spring body formed of pliable sheet material; a hook formed integrally with said body for hooking about a first reach of said sinuous spring; a catch formed integrally with said body at one end thereof adjacent to said hook for engagement with a second reach of the sinuous spring to prevent said hook from being inadvertently displaced relative to said rst reach and to thereby rmly secure the auxiliary spring to the sinuous spring; and a clip formed integrally at the opposite end of said body.

9. In an auxiliary spring adapted to be mounted' in a spring assembly which includes sinuous springs that cornprise a plurality of parallel reaches disposed transverse to the length of the spring and connected to each other successively by semicircular portions; an auxiliary spring body; means at one end of said body for securing the auxiliary spring to a plurality of reaches of the sinuous spring; and a clip formed integrallywith the opposite end of said body for attaching the auxiliary spring to members of the spring assembly.

10. In an auxiliary spring adapted to be mounted on a sinuous spring which comprises a plurality of parallel reaches disposed transverse to the length of the spring and connected to each other successively by semicircular portions; an auxiliary spring body formed of pliable sheet material; a hook formed integrally with said body by bending a portion of the sheet material backwardly to overlap said body, said hook being adapted to hook about a first reach of said sinuous spring; a catch formed integrally with said body by bending the extremity of the sheet material adjacent to said hook outwardly of said hook and said body; and a clip formed integrally at the end of said body opposite said catch by bending the sheet material backwardly into overlying relationship with said body.

11. A spring assembly comprising a pair of spaced frame members, a sinuous spring extending between said frame members and including semicircular portions joined by parallel reaches, and an auxiliary edge spring comprising an integral fiat sheet metal body having first and second ends, said first end including a substantially S-shaped portion extending in spaced overlapping relationship to said body to define a hook and a catch, said hook extending around one reach and said catch extending about an adjacent reach for supporting said auxiliary spring on said sinuous spring, said second end of said auxiliary spring including portion disposed about an edge Wire.

12. A spring assembly as set forth in claim 11 wherein said second end of said auxiliary spring comprises a substantially U-shaped portion, said edge wire being supported in said U-shaped portion.

13. An auxiliary edge spring of the type supported on a sinuous spring strip and comprising: an integral fiat sheet metal body having rst and second ends, said first end havinga` substantially S-shaped portion extending in spaced, overlapping, divergent relationship tosaid body to dene a hook and a catch, said hook and said catch being sufficiently spaced from one another for engaging adjacent reaches of a sinuous spring strip, said seconfd end having substantially U-shaped portion for supporting a border wire. 1 r

14. An auxiliary edge spring as set forth. in claim 13 wherein said U-shaped portion extends rearwardly and in overlapping relationship with said body.

15. An auxiliary edge spring as set forth in claim 14 wherein said S-shaped portion is disposed on the opposite side of saidy body from the U-shaped second end.

References Cited UNITED STATES PATENTS l0 ARTHUR L. LA POINT, Primary Examiner. 

1. IN A SPRING ASSEMBLY FOR MOUNTING ON A FURNITURE FRAME; A SINUOUS SPRING SHAPED TO HAVE ITS LENGTH FOLLOW AN ARCUATE PATH WHEN SAID SPRING IS IN ITS RELAXED CONDITION, A PRESTRESS LEVER FORMED BY A PORTION DISPLACED FROM THE RELAXED PATH OF THE REMAINDER OF THE SPRING, SAID PRESTRESS LEVER SUPPORTED BY THE FURNITURE FRAME AND COUPLED TO SAID SINUOUS SPRING, SAID PRESTRES LEVER EXERTING A PRESTRESS FORCE ON SAID SINUOUS SPRING TO FLATTEN ITS ARCUATE CONFIGURATION WHEN SAID SPRING IS MOUNTED ON THE FURNITURE FRAME TO IMPROVE THE CHARACTERISTICS OF SAID SPRING FOR FURNITURE APPLICATIONS; AN AUXILIARY SPRING EXTENDING FROM SAID SINUOUS SPRING TO PROVIDE A SPRING SUPPORT AT AN EXTREMITY OF THE FURNITURE FRAME; MOUNTING MEANS FOR MOUNTING SAID AUXILIARY SPRING TO SAID SINUOUS SPRING; AND REINFORCING MEANS ON SAID AUXILIARY SPRING IN ENGAGEMENT WITH SAID PRESTRESS LEVER TO REINFORCE SAID PRESTRESS LEVER TO AVOID DAMAGE TO THE SPRING BY THE PRESTRESS FORCES. 